S'well · Insulated Travel Mugs
S'ip by S'well Takeaway Mug
Lower concern; stainless steel tumbler with no reported coatings.
S'well's stainless steel insulated mugs lack PFAS-prone coatings or treatments. Brand is silent on PFAS, but bare stainless construction poses minimal risk.
Shop S'well on Amazon →Material
Stainless steel exterior, insulated
Brand disclosure
Brand is silent on PFAS
Lab data
No public lab test
Why this grade
Safe base material
Made from a material with no inherent PFAS use (ceramic, mineral, or natural fiber).
Category baseline
other is a category where PFAS exposure is more common.
No PFAS disclosure
No public statement about PFAS in this product.
The full breakdown
What it's made of and why it matters
The S'ip by S'well uses a food-grade stainless steel exterior (typically 18/8 or similar austenitic alloy) bonded to an insulating layer, with a plastic or silicone interior liner and lid components. Stainless steel itself is chemically inert and does not leach heavy metals like lead or cadmium under normal use. The critical safety variable is the interior lining material: if it is a durable elastomer (silicone) or polypropylene, it poses minimal risk; if it contains older plastic formulations, there is a small window for BPA or phthalate exposure, particularly if subjected to high heat or prolonged hot beverage contact.
The brand's record and disclosure
S'well (owned by Caldera Brands) has not published detailed third-party safety certifications or material disclosures in public domain, and does not maintain an explicit PFAS-free statement. The brand has no major recalls or documented safety incidents on record for the S'ip line. S'well markets products as BPA-free, though independent verification of all interior components is limited. The company's general silence on manufacturing standards and material sourcing is typical of the sector but leaves some opacity regarding interior sealants and adhesives.
How it compares in its category
Stainless steel insulated tumblers are among the safest reusable drinkware options available because they avoid the coating-degradation and ceramic-glaze risks of thermal-shock vessels. S'well's price point and design place it in the premium segment; competitors like Hydro Flask and YETI use similar stainless construction. Unlike ceramic or coated metal alternatives, this category carries virtually no risk of lead, cadmium, or Teflon-type coating fume exposure. The main differentiator is lid and interior gasket durability, which varies by brand maintenance and material quality.
If you buy it
Use only with beverages under 80C (176F) to avoid stressing interior seals; repeated boiling-water contact can degrade elastomer liners over years. Hand-wash the lid assembly thoroughly, as crevices can harbor bacterial biofilm if stored damp. Inspect the interior seal annually for discoloration, odor, or visible degradation; replace if compromised. Store dry and avoid prolonged contact with acidic beverages (citrus, vinegar) in the lid, which can corrode stainless steel over extended periods, though the tumbler itself is corrosion-resistant.
Beyond PFAS: other things we checked
Established hazard classes for this product type, assessed from public information. These never change the PFAS grade; a Likely flag caps the Verdict at “Buy with care.”
BPA/BPS in interior lining or gaskets
S'well states products are BPA-free, but independent lab confirmation of all interior components is not publicly available. Risk is low for cold beverages but increases with hot-liquid prolonged contact.
Bacterial growth in lid seals
Silicone or rubber gaskets can harbor Listeria, E. coli, or mold if moisture is trapped and drying is incomplete. This is a use-maintenance issue, not a manufacturing defect.
Phthalates in plastic components
No documented cases or recalls; stainless and food-grade silicone alternatives to vinyl are now standard in this price category, making phthalate exposure unlikely.
Heavy metals in stainless steel or adhesives
Stainless steel 18/8 alloy contains nickel (8-11%) and chromium, both present as stable oxides that do not leach under normal beverage pH. Nickel sensitivity can occur in individuals with contact dermatitis, but ingestion risk is negligible.
Thermal shock or seal failure from temperature cycling
Repeated exposure to boiling water followed by cold storage can stress the bond between stainless and insulation, and degrade interior elastomer seals, potentially releasing volatile compounds or allowing metal-to-plastic contact.
What we don’t know
This grade is a model-based estimate from public materials, coatings, and brand disclosure at 72% confidence. It is not a lab result.
No independent PFAS lab test is on record for this exact product. A lab test could move the score in either direction.
The brand has not made a specific, verifiable PFAS-free statement, so part of this score reflects that missing disclosure rather than a confirmed material.
Formulations and coatings change between production runs. Always check the current label before buying.
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More insulated travel mugs grades
How we score: every product runs through the same public 0–100 rubric based on materials, coatings, brand disclosure, lab findings, and recalls. See the full methodology → Spotted a mistake? Report an error.